napi-rs/README.md

# napi-rs

> This project was initialized from [xray](https://github.com/atom/xray)

A minimal library for building compiled `NodeJS` add-ons in `Rust`.

<p>
  <a href="https://docs.rs/crate/napi"><img src="https://docs.rs/napi/badge.svg"></img></a>
  <a href="https://crates.io/crates/napi"><img src="https://img.shields.io/crates/v/napi.svg"></img></a>
  <a href="https://www.npmjs.com/package/napi-rs"><img src="https://img.shields.io/npm/v/napi-rs.svg"></img></a>
</p>

# Platform Support

![](https://github.com/napi-rs/napi-rs/workflows/macOS/badge.svg)
![](https://github.com/napi-rs/napi-rs/workflows/Linux/badge.svg)
![](https://github.com/napi-rs/napi-rs/workflows/Windows/badge.svg)

## Operating Systems

| Linux | macOS | Windows x64 MSVC |
| ----- | ----- | ---------------- |
| ✓     | ✓     | ✓                |

## NodeJS

| Node10 | Node 12 | Node14 |
| ------ | ------- | ------ |
| ✓      | ✓       | ✓      |

This library depends on N-API and requires `Node@8.9` or later.

We already have some packages written by `napi-rs`: [node-rs](https://github.com/napi-rs/node-rs)

One nice feature is that this crate allows you to build add-ons purely with the `Rust` toolchain and without involving `node-gyp`.

## Taste

> You can start from [package-template](https://github.com/napi-rs/package-template) to play with `napi-rs`

### Define JavaScript functions

```rust
#[js_function(1)] // ------> arguments length, omit for zero
fn fibonacci(ctx: CallContext) -> Result<JsNumber> {
  let n = ctx.get::<JsNumber>(0)?.try_into()?;
  ctx.env.create_int64(fibonacci_native(n))
}

#[inline]
fn fibonacci_native(n: i64) -> i64 {
  match n {
    1 | 2 => 1,
    _ => fibonacci_native(n - 1) + fibonacci_native(n - 2),
  }
}
```

### Register module

```rust
/// test_module is Module name
register_module!(test_module, init);

/// Module is `module` object in NodeJS
fn init(module: &mut Module) -> Result<()> {
  module.create_named_method("fibonacci", fibonacci)?;
}
```

## Building

This repository is a Cargo crate. Any napi-based add-on should contain `Cargo.toml` to make it a Cargo crate.

In your `Cargo.toml` you need to set the `crate-type` to `"cdylib"` so that cargo builds a C-style shared library that can be dynamically loaded by the Node executable. You'll also need to add this crate as a dependency.

```toml
[lib]
crate-type = ["cdylib"]

[dependencies]
napi = "0.5"
napi-derive = "0.5"

[build-dependencies]
napi-build = "0.2"
```

And create `build.rs` in your own project:

```rust
// build.rs
extern crate napi_build;

fn main() {
  napi_build::setup();
}
```

So far, the `napi` build script has only been tested on `macOS` `Linux` and `Windows x64 MSVC`.

See the included [test_module](./test_module) for an example add-on.

Run `cargo build` to produce the `Dynamic lib` file. And install the `napi-rs` to help you copy `Dynamic lib` file to `.node` file in case you can `require` it in your program.

```json
{
  "package": "your pkg",
  "devDependencies": {
    "napi-rs": "latest"
  },
  "scripts": {
    "build": "cargo build && napi build",
    "build-release": "cargo build --release && napi build --release"
  }
}
```

Then you can require your native binding:

```js
require('./target/debug|release/[module_name].node')
```

The `module_name` would be your `package` name in your `Cargo.toml`.

`xxx => ./target/debug|release/xxx.node`

`xxx-yyy => ./target/debug|release/xxx_yyy.node`

You can also copy `Dynamic lib` file to an appointed location:

```bash
napi build [--release] .
napi build [--release] ./mylib
```

## Testing

Because libraries that depend on this crate must be loaded into a Node executable in order to resolve symbols, all tests are written in JavaScript in the `test_module` subdirectory.

To run tests:

```sh
yarn --cwd ./test_module build
yarn test
```

## Features table

### Create JavaScript values

| NAPI                                                                                                         | NAPI Version | Minimal Node version | Status |
| ------------------------------------------------------------------------------------------------------------ | ------------ | -------------------- | ------ |
| [Enum types](https://nodejs.org/api/n-api.html#n_api_enum_types)                                             | 6            | v13.7.0              | ⛔️    |
| [napi_create_array](https://nodejs.org/api/n-api.html#n_api_napi_create_array)                               | 1            | v8.0.0               | ✅     |
| [napi_create_array_with_length](https://nodejs.org/api/n-api.html#n_api_napi_create_array_with_length)       | 1            | v8.0.0               | ✅     |
| [napi_create_arraybuffer](https://nodejs.org/api/n-api.html#n_api_napi_create_arraybuffer)                   | 1            | v8.0.0               | ✅     |
| [napi_create_buffer](https://nodejs.org/api/n-api.html#n_api_napi_create_buffer)                             | 1            | v8.0.0               | ✅     |
| [napi_create_buffer_copy](https://nodejs.org/api/n-api.html#n_api_napi_create_buffer_copy)                   | 1            | v8.0.0               | ⛔️    |
| [napi_create_date](https://nodejs.org/api/n-api.html#n_api_napi_create_date)                                 | 5            | v11.11.0             | ⛔️    |
| [napi_create_external](https://nodejs.org/api/n-api.html#n_api_napi_create_external)                         | 1            | v8.0.0               | ✅     |
| [napi_create_external_arraybuffer](https://nodejs.org/api/n-api.html#n_api_napi_create_external_arraybuffer) | 1            | v8.0.0               | ✅     |
| [napi_create_external_buffer](https://nodejs.org/api/n-api.html#n_api_napi_create_external_buffer)           | 1            | v8.0.0               | ✅     |
| [napi_create_object](https://nodejs.org/api/n-api.html#n_api_napi_create_object)                             | 1            | v8.0.0               | ✅     |
| [napi_create_symbol](https://nodejs.org/api/n-api.html#n_api_napi_create_symbol)                             | 1            | v8.0.0               | ✅     |
| [napi_create_typedarray](https://nodejs.org/api/n-api.html#n_api_napi_create_typedarray)                     | 1            | v8.0.0               | ⛔️    |
| [napi_create_dataview](https://nodejs.org/api/n-api.html#n_api_napi_create_dataview)                         | 1            | v8.3.0               | ⛔️    |
| [napi_create_int32](https://nodejs.org/api/n-api.html#n_api_napi_create_int32)                               | 1            | v8.4.0               | ✅     |
| [napi_create_uint32](https://nodejs.org/api/n-api.html#n_api_napi_create_uint32)                             | 1            | v8.4.0               | ✅     |
| [napi_create_int64](https://nodejs.org/api/n-api.html#n_api_napi_create_int64)                               | 1            | v8.4.0               | ✅     |
| [napi_create_double](https://nodejs.org/api/n-api.html#n_api_napi_create_double)                             | 1            | v8.4.0               | ✅     |
| [napi_create_bigint_int64](https://nodejs.org/api/n-api.html#n_api_napi_create_bigint_int64)                 | 6            | v10.7.0              | ✅     |
| [napi_create_bigint_uint64](https://nodejs.org/api/n-api.html#n_api_napi_create_bigint_uint64)               | 6            | v10.7.0              | ✅     |
| [napi_create_bigint_words](https://nodejs.org/api/n-api.html#n_api_napi_create_bigint_words)                 | 6            | v10.7.0              | ✅     |
| [napi_create_string_latin1](https://nodejs.org/api/n-api.html#n_api_napi_create_string_latin1)               | 1            | v8.0.0               | ✅     |
| [napi_create_string_utf16](https://nodejs.org/api/n-api.html#n_api_napi_create_string_utf16)                 | 1            | v8.0.0               | ✅     |
| [napi_create_string_utf8](https://nodejs.org/api/n-api.html#n_api_napi_create_string_utf8)                   | 1            | v8.0.0               | ✅     |

### [Functions to convert from N-API to C types](https://nodejs.org/api/n-api.html#n_api_functions_to_convert_from_n_api_to_c_types)

| NAPI                                                                                                 | NAPI Version | Minimal Node Version | Status |
| ---------------------------------------------------------------------------------------------------- | ------------ | -------------------- | ------ |
| [napi_get_array_length](https://nodejs.org/api/n-api.html#n_api_napi_get_array_length)               | 1            | v8.0.0               | ✅     |
| [napi_get_arraybuffer_info](https://nodejs.org/api/n-api.html#n_api_napi_get_arraybuffer_info)       | 1            | v8.0.0               | ✅     |
| [napi_get_buffer_info](https://nodejs.org/api/n-api.html#n_api_napi_get_buffer_info)                 | 1            | v8.0.0               | ✅     |
| [napi_get_prototype](https://nodejs.org/api/n-api.html#n_api_napi_get_prototype)                     | 1            | v8.0.0               | ✅     |
| [napi_get_typedarray_info](https://nodejs.org/api/n-api.html#n_api_napi_get_typedarray_info)         | 1            | v8.0.0               | ⛔️    |
| [napi_get_dataview_info](https://nodejs.org/api/n-api.html#n_api_napi_get_dataview_info)             | 1            | v8.3.0               | ⛔️    |
| [napi_get_date_value](https://nodejs.org/api/n-api.html#n_api_napi_get_date_value)                   | 5            | v11.11.0             | ⛔️    |
| [napi_get_value_bool](https://nodejs.org/api/n-api.html#n_api_napi_get_value_bool)                   | 1            | v8.0.0               | ✅     |
| [napi_get_value_double](https://nodejs.org/api/n-api.html#n_api_napi_get_value_double)               | 1            | v8.0.0               | ✅     |
| [napi_get_value_bigint_int64](https://nodejs.org/api/n-api.html#n_api_napi_get_value_bigint_int64)   | 6            | v10.7.0              | ✅     |
| [napi_get_value_bigint_uint64](https://nodejs.org/api/n-api.html#n_api_napi_get_value_bigint_uint64) | 6            | v10.7.0              | ✅     |
| [napi_get_value_bigint_words](https://nodejs.org/api/n-api.html#n_api_napi_get_value_bigint_words)   | 6            | v10.7.0              | ✅     |
| [napi_get_value_external](https://nodejs.org/api/n-api.html#n_api_napi_get_value_external)           | 1            | v8.0.0               | ✅     |
| [napi_get_value_int32](https://nodejs.org/api/n-api.html#n_api_napi_get_value_int32)                 | 1            | v8.0.0               | ✅     |
| [napi_get_value_int64](https://nodejs.org/api/n-api.html#n_api_napi_get_value_int64)                 | 1            | v8.0.0               | ✅     |
| [napi_get_value_string_latin1](https://nodejs.org/api/n-api.html#n_api_napi_get_value_string_latin1) | 1            | v8.0.0               | ✅     |
| [napi_get_value_string_utf8](https://nodejs.org/api/n-api.html#n_api_napi_get_value_string_utf8)     | 1            | v8.0.0               | ✅     |
| [napi_get_value_string_utf16](https://nodejs.org/api/n-api.html#n_api_napi_get_value_string_utf16)   | 1            | v8.0.0               | ✅     |
| [napi_get_value_uint32](https://nodejs.org/api/n-api.html#n_api_napi_get_value_uint32)               | 1            | v8.0.0               | ✅     |
| [napi_get_boolean](https://nodejs.org/api/n-api.html#n_api_napi_get_boolean)                         | 1            | v8.0.0               | ✅     |
| [napi_get_global](https://nodejs.org/api/n-api.html#n_api_napi_get_global)                           | 1            | v8.0.0               | ✅     |
| [napi_get_null](https://nodejs.org/api/n-api.html#n_api_napi_get_null)                               | 1            | v8.0.0               | ✅     |
| [napi_get_undefined](https://nodejs.org/api/n-api.html#n_api_napi_get_undefined)                     | 1            | v8.0.0               | ✅     |

### [Working with JavaScript Values and Abstract Operations](https://nodejs.org/api/n-api.html#n_api_working_with_javascript_values_and_abstract_operations)

| NAPI                                                                                                 | NAPI Version | Minimal Node Version | Status |
| ---------------------------------------------------------------------------------------------------- | ------------ | -------------------- | ------ |
| [napi_coerce_to_bool](https://nodejs.org/api/n-api.html#n_api_napi_coerce_to_bool)                   | 1            | v8.0.0               | ✅     |
| [napi_coerce_to_number](https://nodejs.org/api/n-api.html#n_api_napi_coerce_to_number)               | 1            | v8.0.0               | ✅     |
| [napi_coerce_to_object](https://nodejs.org/api/n-api.html#n_api_napi_coerce_to_object)               | 1            | v8.0.0               | ✅     |
| [napi_coerce_to_string](https://nodejs.org/api/n-api.html#n_api_napi_coerce_to_string)               | 1            | v8.0.0               | ✅     |
| [napi_typeof](https://nodejs.org/api/n-api.html#n_api_napi_typeof)                                   | 1            | v8.0.0               | ✅     |
| [napi_instanceof](https://nodejs.org/api/n-api.html#n_api_napi_instanceof)                           | 1            | v8.0.0               | ✅     |
| [napi_is_array](https://nodejs.org/api/n-api.html#n_api_napi_is_array)                               | 1            | v8.0.0               | ✅     |
| [napi_is_arraybuffer](https://nodejs.org/api/n-api.html#n_api_napi_is_arraybuffer)                   | 1            | v8.0.0               | ✅     |
| [napi_is_buffer](https://nodejs.org/api/n-api.html#n_api_napi_is_buffer)                             | 1            | v8.0.0               | ✅     |
| [napi_is_date](https://nodejs.org/api/n-api.html#n_api_napi_is_date)                                 | 1            | v8.0.0               | ✅     |
| [napi_is_error](https://nodejs.org/api/n-api.html#n_api_napi_is_error_1)                             | 1            | v8.0.0               | ✅     |
| [napi_is_typedarray](https://nodejs.org/api/n-api.html#n_api_napi_is_typedarray)                     | 1            | v8.0.0               | ✅     |
| [napi_is_dataview](https://nodejs.org/api/n-api.html#n_api_napi_is_dataview)                         | 1            | v8.3.0               | ✅     |
| [napi_strict_equals](https://nodejs.org/api/n-api.html#n_api_napi_strict_equals)                     | 1            | v8.0.0               | ✅     |
| [napi_detach_arraybuffer](https://nodejs.org/api/n-api.html#n_api_napi_detach_arraybuffer)           | Experimental | v13.3.0              | ⛔️    |
| [napi_is_detached_arraybuffer](https://nodejs.org/api/n-api.html#n_api_napi_is_detached_arraybuffer) | Experimental | v13.3.0              | ⛔️    |